Lightweight support structures have, in the past, been used to provide a frame for "sling"-type chairs, i.e., chairs in which the seating surface consists of a piece of flexible fabric support either at its four corners or along two nonadjacent sides. The fabric is usually sized such that, when attached to the frame, it is not taut, but drapes somewhat and thus provides both posterior and back support.
Often the support structure has been made up of a number of support members which are pivotably attached to one another, such that the chair may be collapsed for transportation, etc. Fenby, U.S. Pat. No. 244,216 and Morgan, U.S. Pat. No. 2,689,602 disclose such support structures.
More recently, support structures, constructed solely of pure tension members and pure compression members have been devised. The pure compression members are commonly struts (e.g., poles), the ends of which are interconnected by the pure tension members, usually cables or ropes. Support structures of this type, examples of which are to be found in Miller, U.S. Pat. No. 4,148,520 and Wiesner, U.S. Pat. No. 3,901,551, have been termed "tensegrity" (or "tensional-integrity") types of structures.
The term "tensegrity" was apparently coined by Buckminster Fuller, to describe structures which, as described in Fuller, R. B., Synergetics, Collier MacMillian (1975), have the ability "to yield increasingly without ultimately breaking or coming asunder". Such structures inherently lack rigidity. A more comprehensive treatment of tensegrity is to be found in the above referenced work.